search for: caml_leave_blocking_section

Since OCaml 4 the old and confusing caml_enter_blocking_section and caml_leave_blocking_section calls have been replaced with caml_release_runtime_system and caml_acquire_runtime_system (in that order). Use the new names. --- generator/OCaml.ml | 5 +++-- ocaml/guestfs-c.c | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/generator/OCaml.ml b/generator/OCaml.ml inde...

No action required here as I have pushed this already, this is just for your information. Rich.

...escription_fn; static value can_cache_fn; static value can_extents_fn; @@ -311,6 +314,64 @@ preconnect_wrapper (int readonly) CAMLreturnT (int, 0); } +static int +list_exports_wrapper (int readonly, int is_tls, struct nbdkit_exports *exports) +{ + CAMLparam0 (); + CAMLlocal2 (rv, v); + + caml_leave_blocking_section (); + + rv = caml_callback2_exn (list_exports_fn, Val_bool (readonly), + Val_bool (is_tls)); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int,...

...escription_fn; static value can_cache_fn; static value can_extents_fn; @@ -311,6 +314,65 @@ preconnect_wrapper (int readonly) CAMLreturnT (int, 0); } +static int +list_exports_wrapper (int readonly, int is_tls, struct nbdkit_exports *exports) +{ + CAMLparam0 (); + CAMLlocal2 (rv, v); + + caml_leave_blocking_section (); + + rv = caml_callback2_exn (list_exports_fn, Val_bool (readonly), + Val_bool (is_tls)); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int,...

On Wed, May 15, 2019 at 10:57:58PM -0500, Eric Blake wrote: > +static int > +can_cache_wrapper (void *h) > +{ > + CAMLparam0 (); > + CAMLlocal1 (rv); > + > + caml_leave_blocking_section (); > + > + rv = caml_callback_exn (can_cache_fn, *(value *) h); > + if (Is_exception_result (rv)) { > + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); > + caml_enter_blocking_section (); > + CAMLreturnT (int, -1); > + } > + > +...

...ff --git a/ocaml/guestfs-c.c b/ocaml/guestfs-c.c index 3888c9456..bcf8e6ab3 100644 --- a/ocaml/guestfs-c.c +++ b/ocaml/guestfs-c.c @@ -395,12 +395,16 @@ event_callback_wrapper (guestfs_h *g, /* Ensure we are holding the GC lock before any GC operations are * possible. (RHBZ#725824) */ - caml_leave_blocking_section (); + bool in_blocking_section = (caml_state == NULL); + + if (in_blocking_section) + caml_leave_blocking_section (); event_callback_wrapper_locked (g, data, event, event_handle, flags, buf, buf_len, array, array_len); - caml_enter_blocking_section ();...

...--------*/ /* Wrapper functions that translate calls from C (ie. nbdkit) to OCaml. */ @@ -638,6 +641,48 @@ extents_wrapper (void *h, uint32_t count, uint64_t offset, uint32_t flags, CAMLreturnT (int, 0); } +static int +can_cache_wrapper (void *h) +{ + CAMLparam0 (); + CAMLlocal1 (rv); + + caml_leave_blocking_section (); + + rv = caml_callback_exn (can_cache_fn, *(value *) h); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + caml_enter_blocking_section (); + CAMLretu...

...---------------------------------*/ /* Wrapper functions that translate calls from C (ie. nbdkit) to OCaml. */ @@ -726,6 +728,25 @@ can_fast_zero_wrapper (void *h) CAMLreturnT (int, Bool_val (rv)); } +static int +preconnect_wrapper (int readonly) +{ + CAMLparam0 (); + CAMLlocal1 (rv); + + caml_leave_blocking_section (); + + rv = caml_callback_exn (preconnect_fn, Val_bool (readonly)); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + caml_enter_blocking_section (); +...

...---------*/ /* Wrapper functions that translate calls from C (ie. nbdkit) to OCaml. */ @@ -683,18 +686,30 @@ cache_wrapper (void *h, uint32_t count, uint64_t offset, uint32_t flags) CAMLreturnT (int, 0); } +static int +thread_model_wrapper (void) +{ + CAMLparam0 (); + CAMLlocal1 (rv); + + caml_leave_blocking_section (); + + rv = caml_callback_exn (config_complete_fn, Val_unit); + if (Is_exception_result (rv)) { + nbdkit_error ("%s", caml_format_exception (Extract_exception (rv))); + caml_enter_blocking_section (); + CAMLreturnT (int, -1); + } + + caml_enter_blocking_section (); + CAMLre...

This bug was found by Eric Blake. In the .pread method we allocate a buffer in the server and pass it to the plugin. The plugin is supposed to fill it with data. The buffer was uninitialized so initially contained random heap data, but that's OK provided the plugin fully overwrote it with data. All correctly written plugins ought to do this, however there is the possibility of an

...ugins/ocaml/ocaml.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/plugins/ocaml/ocaml.c b/plugins/ocaml/ocaml.c index d854f48..7193842 100644 --- a/plugins/ocaml/ocaml.c +++ b/plugins/ocaml/ocaml.c @@ -444,6 +444,10 @@ pread_wrapper (void *h, void *buf, uint32_t count, uint64_t offset, caml_leave_blocking_section (); strv = caml_alloc_string (count); + /* Initialize the buffer with zeroes in case the plugin does not + * fill it completely. + */ + memset (String_val (strv), 0, count); offsetv = caml_copy_int64 (offset); flagsv = Val_flags (flags); -- 2.20.1

This picks up python and ocaml. Some of our languages are lacking a number of bindings (for example, lua and perl lack .extents, so I didn't have anything to copy from), and I felt less comfortable with golang and rust. But for python and ocaml, I was able to test a working implementation. Eric Blake (2): python: Implement .list_exports and friends ocaml: Implement .list_exports and

...gins/ocaml/ocaml.c +++ b/plugins/ocaml/ocaml.c @@ -439,15 +439,16 @@ pread_wrapper (void *h, void *buf, uint32_t count, uint64_t offset, uint32_t flags) { CAMLparam0 (); - CAMLlocal4 (rv, strv, offsetv, flagsv); + CAMLlocal4 (rv, countv, offsetv, flagsv); + mlsize_t len; caml_leave_blocking_section (); - strv = caml_alloc_string (count); + countv = caml_copy_int32 (count); offsetv = caml_copy_int64 (offset); flagsv = Val_flags (flags); - value args[] = { *(value *) h, strv, offsetv, flagsv }; + value args[] = { *(value *) h, countv, offsetv, flagsv }; rv = caml_callbackN_exn...

...t;; - pr "static void\n"; + pr "static int\n"; pr "%s_%s_wrapper " name cb_name; print_c_arg_list args; pr "\n"; pr "{\n"; + pr " int ret;\n"; + pr "\n"; pr " caml_leave_blocking_section ();\n"; let c_argnames = List.flatten (List.map name_of_arg args) in - pr " %s_%s_wrapper_locked (%s);\n" name cb_name + pr " ret = %s_%s_wrapper_locked (%s);\n" name cb_name (String.concat ", " c_argnames); pr " caml...

...quot;NULL" + | RUInt -> pr " unsigned r;\n"; None in pr "\n"; pr " caml_enter_blocking_section ();\n"; pr " r = nbd_%s " name; @@ -4757,14 +4781,17 @@ let print_ocaml_binding (name, { args; ret }) = pr ";\n"; pr " caml_leave_blocking_section ();\n"; pr "\n"; - pr " if (r == %s)\n" errcode; - pr " nbd_internal_ocaml_raise_error ();\n"; - pr "\n"; + (match errcode with + | Some code -> + pr " if (r == %s)\n" code; + pr " nbd_internal_ocaml_raise_err...

...name; - C.print_arg_list ~user_data:true cbargs; + C.print_arg_list ~valid_flag:true ~user_data:true cbargs; pr "\n"; pr "{\n"; - pr " int ret;\n"; + pr " int ret = 0;\n"; pr "\n"; - pr " caml_leave_blocking_section ();\n"; - pr " ret = %s_%s_wrapper_locked " name cbname; + pr " if (valid_flag & LIBNBD_CALLBACK_VALID) {\n"; + pr " caml_leave_blocking_section ();\n"; + pr " ret = %s_%s_wrapper_locked " name cbname; C.print_...

On Windows, there exist at least two APIs for dealing with the Registry: The Win32 API (RegCreateKeyA, RegCreateKeyW, etc.) works with null-terminated ASCII or UTF-16 strings. The native API (ZwCreateKey, etc.), on the other hand works with UTF-16 strings that are stored as buffers+length and may contain null characters. Malware authors have been relying on the Win32 API's inability to

Version 1 was here: https://www.redhat.com/archives/libguestfs/2019-April/msg00144.html Version 2 makes a couple of much larger changes: The OCaml patch changes the API of the pread method so it matches what other language bindings are already doing, ie. get the language plugin to return a newly allocated buffer, check it is long enough, copy out the data. The server patch implements a

...name; - C.print_arg_list ~user_data:true cbargs; + C.print_arg_list ~valid_flag:true ~user_data:true cbargs; pr "\n"; pr "{\n"; - pr " int ret;\n"; + pr " int ret = 0;\n"; pr "\n"; - pr " caml_leave_blocking_section ();\n"; - pr " ret = %s_%s_wrapper_locked " name cbname; + pr " if (valid_flag & LIBNBD_CALLBACK_VALID) {\n"; + pr " caml_leave_blocking_section ();\n"; + pr " ret = %s_%s_wrapper_locked " name cbname; C.print_...

...pr "static int\n"; - pr "%s_%s_wrapper " name cbname; - C.print_arg_list ~user_data:true cbargs; - pr "\n"; - pr "{\n"; - pr " int ret;\n"; - pr "\n"; - pr " caml_leave_blocking_section ();\n"; - pr " ret = %s_%s_wrapper_locked " name cbname; - C.print_arg_list ~user_data:true ~types:false cbargs; - pr ";\n"; - pr " caml_enter_blocking_section ();\n"; - pr " return ret;\n"; -...